QRP Low Power, that is less than 5 watts, sometimes stretches to 10 watts. It appears that low power radios that have a battery included built-in, may actually be operating well below 1 watt, on that battery. Only when an external 13.8v is connected will the “full” power be available (sometimes as much as 20 watts).
Low Power typically implies smaller, light weight and lower priced equipment, so connecting QRP to the “Portable” category, but not everyone likes to get involved with taking equipment outside or on the road. As described elsewhere on these pages, I bought a TruSDX as an entry into HF. It was the lowest priced rig that seemed to be well designed, by HAMS, with a good user-base and on-going development. I didn’t want to spend $1500 on a radio, just to find that I needed a $500 antenna and an ever increasing list of other parts such as batteries, tuners, amplifiers, filters etc. and I might get board with it. I knew I would need to make a basic antenna, but the recommended linked dipole didn’t look too complex or expensive and I could back that up with an even cheaper and more manageable End Fed Half Wave wire-line. The TruSDX takes 5v power via the USB part, but only provides milli-watts that way, so the alternative dc in socket would need a 12-15v supply (13.8v recommended) to get toward the 5 watt maximum.